Starting Issue…

I only see one mention of auto decompression in the shop manual and that's just that it has it. It obviously doesn't work with the engine off or you'd have to compensate when checking the valve clearance.

Can anyone explain how this works?

So, it looks as if the decomp valve / cam is the culprit. “No abnormal resistance exists in this system” according to my consultant. He better have been right, because I had to pay dearly for that edict (someone pass the highland!)

So now my more serious concern: Can I run the LA to Vegas DS run after T-Day with this affliction, or should a get my ass down to Santa Ana on the double ? :cripple:

Oh yeah, I called him to ask if I could borrow a voltmeter, and that ended with “Well why don’t you just bring your bike over and ‘we’ll’ take a look at it.”

Gotta love the guy for lending a hand, but I just had flashbacks of math lessons gone awry from my youth the entire time. As a result I suck at math and still don’t understand magic (oops, I mean electricity…)

I asked him why the car battery cranked it up like a squirrel on meth, and he told me that the car battery outputted 3x the amperage of the motorcycle battery, so it had more than enough power to overcome the excessive compression. He also tried to explain why the added amperage would eventually burn out the thingy…

Seriously, does anyone know how this auto decompression system works? My bike has never spun over if it lands too close to TDC on the compression stroke without using the manual decomp.. So if there is a automatic system that should be working I need to fix it.

Theres an angled weight on the end of the exhaust cam that, at cranking speed, just clips the edge of the valve shim to open the valve slightly. Once the engine is running the centrifugal force moves the weight away from the valve shim allowing the valve to close fully.

If there is too much clearance between the weight and the cam or the rocker has excessive lateral play then the weight will miss the shim and the auto decompressor doesn't work. It has been known to have to replace the spring clip on the rocker shaft to keep the rocker arm in place.

If you lean the bike over to the right when starting (or before) sometimes the rocker will move in place and the auto decompressor work.

Having said all that, it is very important to keep the battery in top condition on 450/510 with EFI as it has a lot of work to do, especially in cold conditions. IMHO if the bike starts using the manual decompressor then it's probably not worth the effort of ripping the cam out and trying to fix it.

Very cool info Dave P - Thanks!!

Yes, thank you very much davep01.

Exactly what I have found. I use the manual de-comp to get it spinning every time now. While that works great, it would be nice to find out what's up with the auto de-comp.

Scott Summers wrote in his DirtBike mag. artical; "Did you know the TXC (carburetor) and the TE (fuel injected) both have kick and electric start and they will start dead engine as fast as a two stroke?"

I'd have to say "NO" to that, because mine has never been that way.

Is that just the TXC's ?

I've spent many hours dealing with this on my 05'. I've heard of "improved decompression system" for 08 but have yet to confirm what they actually did to improve it. Check out my web page about TE510 Starting Problem Solved

Worked for me!

Good stuff "X". I never realized that was what that thing was supposed to do because mine set so far from the rocker. I'll have to open it back up and try to figure out what's wrong with it.

Funny thing about this is that I was sitting talking to Scott one day right after I got my bike and when I went to start it, it wouldn't turn over. I thought the battery was dead, but said that happens sometimes and I should pull in the manual lever and use the kick start to run it past TDC. I did and it worked, so that's the way I've been doing it since then.

At races the rest of the guys are so far gone by the time I get me bike started, it looks like I started from the next row. Maybe this will get me back to getting holeshots again.

I ordered a battery tender, a new Valve lifter, valve shim kit and have a new battery. I'm going to try and get all this stuff working 100% and see if I can get this thing off the line with the pack. Then maybe I can start winning some races again.

Any final determination/resolution to this?

C

Just got the lifter the other day, but I'm going to try to get into it this weekend.

M, what does the "valve shim kit" consist of. Is Husky making some kind of camshaft shim like I rigged up?

I ordered a new decomp lifter from Hall's along with the tech manual CD. Haven't gotten them yet, hopefully soon...

These are just the standard valve shims. What did you rig up?

There's nothing about the auto decompression in the manual, that I can find anyway.